JPH02281012A - Method for producing new polymer particles - Google Patents

Abstract

PURPOSE:To obtain the subject particle having excellent moldability, rigidity, dimensional accuracy, etc., by heating an aqueous suspension containing copolymer particles, a vinyl monomer and a radical polymerization initiator at specific ratios at a temperature below the decomposition point of the initiator to effect the impregnation of the monomer into the copolymer particles and polymerizing the monomer under heating. CONSTITUTION:The objective polymer particle can be produced by preparing an aqueous suspension containing 100 pts.wt. of particles of a copolymer composed mainly of a dialkenylbenzene of formula (R<1> is H or CH3; R<2> is 1 to 6C hydrocarbon group; (n) is 0 or 1) and propylene, 5 to 200 pts.wt. of a vinyl or vinylidene monomer and 0.01 to 3 pts.wt. (based on 100 pts.wt. of the vinyl or vinylidene monomer) of a radical polymerization initiator having a decomposition temperature of 85 to 130 deg.C corresponding to the half-life to 10hr, impregnating the monomer into the polymer particle to decrease the free vinyl or vinylidene monomer to <20wt.% by heating the aqueous suspension under a condition not to cause the decomposition of the initiator, and polymerizing the monomer by raising the temperature of the aqueous suspension.

Description

[Detailed Description of the Invention] [Background of the Invention] Technical Field The present invention relates to a dialkenylbenzene that has excellent moldability, improved properties such as rigidity, dimensional accuracy, and printability, and is suitable as a compatibilizer. - A method for producing propylene copolymer (hereinafter sometimes referred to as a specific propylene copolymer) particles.

More specifically, the present invention relates to a method for producing a homogeneous composite resin comprising a specific propylene copolymer and a vinyl polymer. This composite resin maintains its homogeneity even if the vinyl polymer is contained in a larger amount than the specific propylene copolymer within a limited range.

Accordingly, another aspect of the invention relates to a method for producing modified vinyl polymers.

Prior Art In order to improve the rigidity, dimensional stability, printability, etc. of propylene polymers used as molding materials, it has been conventionally practiced to blend olefin polymers with vinyl polymers, such as polystyrene.

However, since olefin polymers and polystyrene generally have poor compatibility, polystyrene is not added in an amount of 10% by weight or more, and generally 0.2 to 5% by weight is used.
Only a weight percent of polystyrene was blended into the olefin polymer.

However, even when such a small amount of polystyrene is blended, molded articles made from the blend tend to have reduced impact resistance and poor appearance due to poor compatibility between the two resins.

In order to improve these drawbacks, a method has been proposed in which styrene is graft-polymerized onto a propylene polymer by irradiation with ionizing radiation.

Although this method is effective in uniformly dispersing polystyrene into propylene polymer, it has not been put to practical use because it uses a special method called radiation graft polymerization and has economical problems. Note that this method has a limit to the amount of styrene that can be introduced.

On the other hand, another known method is a method in which a propylene polymer is dissolved in a solvent such as xylene or chlorobenzene, and styrene or the like is graft-polymerized using a radical polymerization initiator, that is, a solution graft polymerization method. However, in this method, due to the solubility of the propylene polymer, polymerization is carried out diluted in a large amount of solvent, so there is no chance of the vinyl monomer, polymerization initiator, and propylene polymer coming into contact with each other. In addition, it has the disadvantage that the reaction efficiency of the vinyl monomer is low, and the post-processing steps such as solvent recovery are complicated, so it is economically disadvantageous. There is also an emulsion graft polymerization method, but in this case, the polymerization is limited to the surface reaction of the propylene polymer particles, which has the disadvantage of poor homogeneity of the product.

On the other hand, a method for modifying propylene with styrene using an aqueous suspension method is known as a method for improving these drawbacks. However, this styrene-modified propylene is still unsatisfactory as a compatibilizer, and a higher performance one is desired.

[Summary of the invention]

Summary of the Invention The present invention aims to solve the above-mentioned problems by using only a single step of suspension polymerization of vinyl monomers, and by carrying out this suspension polymerization step under specific conditions. This aims to achieve this purpose.

Therefore, the method for producing novel polymer particles according to the present invention is characterized by comprising the following steps (A) and (B).

100 parts by weight of particles of a copolymer mainly composed of dialkenylbenzene and propylene represented by: 5 to 200 parts by weight of a vinyl or vinylidene monomer, and a decomposition temperature of 85 to 130°C to obtain a half-life of 10 hours. An aqueous suspension containing a radical polymerization initiator of 0.01 to 1 part of B1ff per 100 parts by weight of the vinyl or vinylidene monomer is heated under conditions that do not substantially cause decomposition of the initiator, The vinyl or vinylidene monomer is impregnated into the olefin polymer particles to achieve an amount of free vinyl or vinylidene monomer of less than 20% by weight.

(B) Raise the temperature of the aqueous suspension to complete polymerization of the vinyl or vinylidene monomer.

<Effects> As described above, the method for producing novel polymer particles according to the present invention provides a method for producing polymer particles containing vinyl or vinylidene monomer (hereinafter referred to as vinyl monomer) dissolved in a polymerization initiator for propylene copolymer particles in an aqueous suspension. The method includes an impregnation step (called 1) and a polymerization step of this vinyl monomer. This technology succeeded in producing a homogeneous composite resin material. As a result of impregnating the vinyl monomer to such an extent that the amount of free monomer, that is, the monomer that is not impregnated or attached to the propylene copolymer particles, is less than 20% by weight of the charged monomer, the vinyl monomer Practically all of the vinyl polymer particles are polymerized inside the propylene copolymer particles, with a very small amount adhering to the surface of the propylene polymer particles, and the vinyl polymer particles exist independently from the propylene copolymer particles in the product. is virtually unacceptable. Therefore,
In this sense, the method of the present invention can be said to be different from conventional aqueous suspension polymerization of oil-soluble vinyl monomers such as styrene.

Since most of the vinyl monomer is polymerized within the propylene copolymer particles in this way, it is presumed that the produced vinyl polymer is undergoing some kind of interaction with the propylene copolymer, and therefore, there is some interaction between the two. Compatibility is extremely good. Furthermore, compared to known techniques, the vinyl monomer is impregnated into the center of the polymer particles and then polymerized, resulting in excellent homogeneity.

The composite resin obtained by this invention has good compatibility between both types of combined components, so it can be used as a homogeneous molding material, but another feature of this composite resin is that it is compatible with other thermoplastic resins. This means that the compatibility is good.

Therefore, this composite resin may be blended with other thermoplastic resins to form a single molding material, or may contain two or more thermoplastic resins that are compatible with it but not mutually compatible.
Used as a dispersant for plastic resins.

The homogeneity of the composite resin obtained by this invention is achieved by providing a step for impregnating the vinyl monomer into the propylene copolymer particles separately from the polymerization step to uniformly impregnate the vinyl Qi Q body.
That is, this is also due to the fact that it is uniformly applied all the way to the center of the propylene copolymer particles.

[Detailed description of the invention]

(I) Propylene copolymer particles impregnated with vinyl monomer> In the present invention, the "copolymer mainly composed of dialkenylbenzene and propylene" is represented by propylene and the following structural formula. It includes copolymers with dialkenylbenzene and mixtures with other olefins mainly consisting of propylene and copolymers with dialkenylbenzene.

The dialkenylbenzene that characterizes this propylene copolymer may be any isomer such as 〇-isomer, m-isomer, or p-isomer, or may be a mixture.

Various derivatives in which the benzene ring is substituted with other hydrocarbon residues may also be used.

Specific examples of such dialkenylbenzenes include divinylbenzene, isopropenylstyrene, divinyltoluene, and divinylnaphthalene.

On the other hand, the comonomer to be copolymerized with such dialkenylbenzene is propylene or a mixture consisting mainly of propylene (for example, 75% by weight or more) with other α-olefins. In this case, "other olefins" are
Ethylene, aliphatic α-olefins having about 4 to 10 carbon atoms (CoH2n), aliphatic diolefins having about 4 to 10 carbon atoms (for example, butadiene, pentadiene, etc.), and ethylenic non-olefins that can be copolymerized with these. Saturated monomers such as styrene, core and/or side chain substituted styrenes (eg alpha methylstyrene, vinyltoluene), (meth)acrylates, vinyl esters, etc.

This propylene copolymer has a propylene content of 75 to 99.
Preferably, the composition is 95% by weight, dialkenylbenzene 0.05 to 5% by weight, and other α-olefins 0 to 24.95% by weight.

Substantially only one of the two alkenyl groups of this dialkenylbenzene is copolymerized with propylene or the like.

Therefore, since this copolymer is not substantially crosslinked,
Gel content is essentially zero. Incidentally, the copolymerization can be carried out in the same manner as in the production of polypropylene using a so-called Ziegler type catalyst.

Specific examples of propylene copolymers suitable for the present invention include propylene-divinylbenzene copolymer, propylene-ethylene-divinylbenzene copolymer, propylene-butene-1-divinylbenzene copolymer, etc. It is something. These propylene copolymers can also be used in combination. Further, other polymers may be mixed and used within a range that does not impair the properties of the propylene copolymer.

In order to facilitate the impregnation of the vinyl monomer and prevent aggregation during suspension polymerization, the particles of the propylene copolymer have a narrow particle size distribution, an average particle size of 1 to 8+ns+, preferably 3 to 7 layers, If the particle size is too large, not only will it be difficult to disperse during polymerization, but the impregnation rate of the vinyl monomer will be slow (resulting in a long reaction time). When using propylene copolymer particles with a large particle size, for example, 5 to 8, the impregnation time is increased,
Furthermore, the particle size of the propylene copolymer is not necessarily critical in this invention, since it is sufficient to pulverize the resulting resin mass.

According to this invention, the shape of the propylene copolymer particles used is maintained almost unchanged in the produced composite resin, that is, the new polymer particles, so that the produced composite resin has a particle size or particles suitable for immediate use as a molding material. The particle size of the starting propylene copolymer particles can be selected to be similar to the shape.

vinyl monomer As mentioned above, it also includes vinylidene (11-mer).

Specifically, for example, styrenic monomers such as styrene, nuclear-substituted styrene such as methylstyrene, dimethylstyrene, ethylstyrene, isopropylstyrene,
Chlorstyrene, α-substituted styrenes such as α-methylstyrene, α-ethylstyrene, acrylic esters (
In particular, C1-C7 alkyl ester), methacrylic acid ester (especially 01-C7 alkyl ester), vinyl halide or vinylidene (especially vinyl chloride, vinylidene chloride), acrylonitrile, metacyclonitrile, vinylnaphthalene, vinylcarbazole, acrylamide. , methacrylamide, maleic anhydride, and others, which can be used alone or in combination. In particular, hydrophilic or solid vinyl monomers are preferably used dissolved in oil-soluble monomers.

In order to obtain a general purpose and highly rigid modified propylene copolymer, styrene alone or styrene as a main component and a small amount of other monomers copolymerizable with it, especially acrylonitrile, methyl methacrylate, vinyl chloride, anhydrous Mixtures with maleic acid etc. are suitable.

Amount of vinyl monomer used> The amount of vinyl monomer is 5 to 200 parts by weight, preferably 20 to 100 parts by weight, per 100 parts by weight of the propylene copolymer.
Parts by weight. If it exceeds 200 parts by weight, the amount of vinyl monomer that is not impregnated into the propylene copolymer is large (as a result, vinyl polymer particles independent of the propylene copolymer particles are precipitated during suspension polymerization, resulting in a homogeneous composite resin). If the amount is less than 5 parts by weight, the effect of improving the stiffness of the resulting composite resin or the compatibility with other thermoplastic resins will not be sufficient.

According to this invention, as the ratio of vinyl monomer to propylene copolymer increases, the dispersed particle size of the vinyl polymer in the resulting composite resin tends to increase. Therefore, the ratio of the propylene copolymer to the vinyl monomer can be changed depending on the intended use form. −
For example, when the vinyl monomer is styrene, the polystyrene dispersed particle diameter in the composite resin produced is very small when the ratio of styrene is 5 to 100 parts by weight to 100 parts by weight of the propylene copolymer. The resin is effective as a molding material with improved rigidity and dimensional accuracy of propylene copolymer, as a blend material with various thermoplastic resins, and as a dispersant for two or several types of thermoplastic resins that are not compatible with each other. It is. On the other hand, at a ratio of 100 to 200 parts by weight of styrene to 100 parts by weight of propylene copolymer, the dispersed particle size of polystyrene in the resulting composite resin becomes slightly larger, so this comparison resin mainly has high rigidity and durability. Applications are conceivable as a molding material with excellent impact resistance or as a blend material for styrenic resins.

Polymerization initiator> Since the method according to the present invention follows the technique of aqueous suspension polymerization, an oil-soluble polymerization initiator is used.

According to a feature of the present invention, the polymerization initiator must have a decomposition temperature of 85-130°C to obtain a half-life of 10 hours. Particularly preferred is one within the range of 90 to 110°C.

If the temperature is lower than 85°C, polymerization of the vinyl monomer will occur during the impregnation process, making it impossible to obtain a homogeneous composite resin. 130℃
If the amount is exceeded, a molecular cleavage reaction of the propylene copolymer will occur, which is not preferable.

Specific examples of such polymerization initiators are as follows (the temperature in parentheses indicates that if 0.1 mol of the polymerization initiator is added to 1 g of benzene and left at that temperature for 10 hours, polymerization will start). (This is the temperature at which the decomposition rate of the agent is 5026).

Cyclohexanone peroxide (97°C), t-butyl peroxybenzoate (104°C), methyl ethyl ketone peroxide (109°C), dicumyl peroxide (117°C), di-t-butyl peroxide (
124°C), 2,5-dimethyl-2,5-dibenzoylperoxyhexane (100°C), di-t-butyl-di-peroxyphthalate (105°C).

The amount of the polymerization initiator used is 0.01 to 3 parts by weight, preferably 0.1 to 1 part by weight, per 100 parts by weight of the vinyl monomer. If it is less than 0.01 part by weight, the vinyl monomer will not be completely polymerized, and if it exceeds 3 parts by weight, the molecular scission reaction of the propylene copolymer will become significant, and the original physical properties of the propylene copolymer will be significantly impaired. In addition to the damage, the remaining polymerization initiator causes adverse effects when the resulting composite resin is molded.

Furthermore, in the present invention, a single substance or a compound classified as a chain transfer agent can be used in combination during polymerization. Specific examples include (a) aliphatic hydrocarbons such as heptane and cyclohexane; (b) aromatic hydrocarbons such as benzene, toluene, xylene, and naphthalene;
(c) Methanol, ethanol, t as alcohols
-butyl alcohol, polyoxyethylene glycol,
(d) Halogenated hydrocarbons such as chloroform, carbon tetrachloride, bromotrichloromethane, 1,1.1-)lychloroethane, chlorobenzene, chlorotoluene, dichlorobenzene, etc. (v) Ketones such as acetone, methyl ethyl ketone etc., (to)
Aldehydes include acetaldehyde, propionaldehyde, and crotonaldehyde; (t) esters include methyl acetate, ethyl acetate, allyl acetate, and ethyl stearate; (th) amines include trimethylamine and diphenylamine; and (iii) sulfur-containing compounds. acetyl disulfide, sulfur,
α-Toluenethiol, butyl sulfide, etc.
Other examples include dimethylformamide, dioxane, α-methylstyrene dimer, diethyl ether, diethyldithioglycolate, and acetic acid.

Preparation of aqueous suspension> Except for the presence of propylene copolymer particles in the system, the preparation of the aqueous suspension in the present invention is similar to the case where aqueous suspension polymerization of vinyl monomers is carried out. It is essentially no different from that of . Therefore, the propylene copolymer particles and the vinyl monomer, preferably with a predissolved polymerization initiator, are mixed with a suspending agent that can be used for aqueous suspension polymerization, such as water-soluble polymers such as polyvinyl alcohol, polyvinylpyrrolidone, methyl cellulose. It is stirred and dispersed in an aqueous medium in the presence of other or poorly soluble inorganic substances such as phosphoric acid, magnesium oxide, and the like.

The aqueous medium may be one in which various water-soluble substances are dissolved.

The concentration of propylene copolymer particles or vinyl monomer in the aqueous suspension is arbitrary as long as the system can be easily stirred, but in general, the concentration of propylene copolymer particles and vinyl monomer per 100 parts by weight of water is It is carried out in an amount of 5 to 100 parts by weight.

Impregnation of Vinyl Polymer> This aqueous suspension is heated under conditions in which the polymerization initiator used is not substantially decomposed to impregnate the vinyl monomer into the propylene copolymer particles. The impregnation is carried out until at least 80% by weight, preferably at least 90% by weight, of the vinyl monomer is impregnated or deposited on the propylene copolymer particles, i.e. less than 20% by weight, preferably at least 20% by weight, free vinyl monomer droplets are present. The aqueous suspension is preferably left under stirring to an extent of less than 10% by weight. As a result of various experiments conducted by the present inventors, independent vinyl polymer particles precipitate when the unimpregnated vinyl monomer is 20% by weight or more, and the dispersion of the vinyl polymer in the propylene copolymer particles is reduced. It was found that the desired performance could not be obtained due to non-uniformity. In addition, less than 20% by weight of free vinyl monomer in the impregnation step will be impregnated into the propylene copolymer particles or adhered to the surface of the propylene copolymer particles and polymerized in the next polymerization step, so it will not be present in the product. In fact, it is not recognized that the vinyl polymer particles exist independently from the propylene copolymer particles.

During impregnation, the higher the heating temperature, the better from the point of view of promoting impregnation, but since the vinyl monomer before impregnation will polymerize alone due to premature decomposition of the polymerization initiator, heating is recommended to prevent this. The lower the temperature the better. Preferred conditions in the present invention using the above-mentioned specific polymerization initiator and propylene copolymer particles having a specific particle shape are a temperature of 70 to 100° C. and a stirring time of about 2 to 6 hours.

Note that the amount of free vinyl monomer can be determined by the following method. That is, an arbitrary amount of the aqueous suspension is sampled, and this is quickly filtered using a wire mesh of approximately 300 mesh to separate the propylene copolymer particles and the liquid phase, and the amount of vinyl monomer in the liquid phase is determined. The ratio of free vinyl monomer is calculated from this value and the amount of vinyl monomer charged.

[II) Polymerization of vinyl monomer The aqueous suspension thus prepared is further heated to a high temperature, preferably with stirring, to polymerize the vinyl monomer.

The heating temperature should be such that sufficient decomposition of the polymerization initiator used occurs. However, it is preferable not to exceed 150°C. If the temperature exceeds 150°C, a molecular cleavage reaction of the propylene copolymer will occur, and the original properties of the propylene copolymer will be significantly impaired. Generally 100-130
℃ temperature is suitable. The temperature during polymerization does not necessarily have to be constant as long as it is 150° C. or lower, and can be changed to two or more stages depending on the properties of the composite resin produced by suspension polymerization.

Polymerization time is generally 5 to 20 hours.

As described above, the shape of the propylene copolymer particles used is maintained almost unchanged even after the polymerization is completed. After the polymerization is completed, the composite resin is cooled and treated in the same manner as the post-treatment steps of ordinary aqueous suspension polymerization, to immediately obtain a composite resin that can be used as a molding material.

(III) Produced Composite Resin The new polymer particles thus obtained, ie, the composite resin, are not homogeneous to the starting propylene copolymer, but are propylene copolymers containing a homogeneously dispersed vinyl monomer. Estimated to be a modified propylene copolymer in which a polymer or a vinyl carmer is graft-polymerized onto a propylene copolymer backbone, a vinyl monomer polymer graft-polymerized on the surface of a propylene copolymer particle, or an aggregate of these. The unique polymer particles of vinyl monomer are not present separately from the propylene polymer particles.

The composite resin produced according to the present invention is one in which a polymer made from a vinyl monomer is uniformly dispersed in a propylene copolymer as approximately spherical fine particles of 0.1 to 2 μm. Such fine dispersion cannot be achieved by any simple blending method (vinyl polymer particles can be dispersed in propylene copolymer in units of only a few tens of microns).

(IV) Utilization of composite resin The composite resin produced according to the present invention can be utilized as a molding material as a modified propylene copolymer due to its homogeneity. Of course, it is also possible to blend pigments, heat stabilizers, ultraviolet absorbers, antistatic agents, flame retardants, inorganic fillers, and other thermoplastic resins into this composite resin and use it as a molding material.

Another use of this composite resin is to use it as a blend with other thermoplastic resins.

One of the characteristics of the novel polymer of this invention, that is, the composite resin, which is essentially a homopolymer of a propylene copolymer and a vinyl polymer produced by polymerization of a vinyl monomer impregnated into this propylene copolymer. is the good compatibility with various thermoplastic resins, and when this composite resin is blended with various thermoplastic resins in appropriate amounts, it forms a homogeneous blend.
The blend can therefore impart to the incorporated thermoplastic resin the improved properties described above that are unique to this composite resin.

For example, styrene-modified propylene copolymers improve the impact resistance and elongation of homopolystyrene, pigment dispersion, stiffness, and shrinkage of polypropylene, and methyl methacrylate-modified propylene copolymers improve the stiffness and surface properties of polypropylene. Blends of polypropylene with polystyrene and a styrene-modified propylene copolymer have a remarkable effect on improving the extrusion moldability and vacuum moldability of polypropylene.

(V) Examples Example-1 Pure water 21)c in an autoclave with a content of 50 liters
g and 420 g of tribasic calcium phosphate and 0.63 g of sodium dodecylbenzenesulfonate as suspending agents.
was added to form an aqueous suspension, and propylene-divinylbenzene copolymer particles with a particle size of 4 to 5 mm (propylene content: 99.74% by weight, divinylbenzene content: 0.5% by weight) were added.
26ffi amount%, melt index (Ml) 4.1)
7 kg were suspended by stirring. Separately, as a polymerization initiator, t-butyl peroxybenzoate (decomposition temperature to obtain a half-life of 10 hours (the same applies hereinafter): 104°C) 10
．． 5 g of styrene was dissolved in 3.5 kg of styrene, this was added to the suspension system, the IM temperature inside the autoclave was raised to 90°C, and the temperature was maintained for 3 hours to dissolve the styrene containing the polymerization initiator together with propylene. Impregnated into polymer particles.

This aqueous suspension was heated to 105°C and maintained at this temperature for 3 hours to effect polymerization, and further heated to 135°C and maintained at this temperature for 3 hours to complete polymerization.

After cooling, take out the contents, wash with water, and reduce the particle size to 5 to 6 mm.
10.5 kg of styrene-modified propylene copolymer particles were obtained. These particles are free from fusion, agglomeration, and damage.
It was ready for immediate molding.

In addition, using about 1 g of this polymer, Soxhlet extraction was performed using methyl ethyl ketone (MEK) as the extraction solvent.
MEK extraction was carried out for a certain period of time to obtain an insoluble matter. The polystyrene content in the insoluble matter was determined by infrared absorption spectroscopy, and the ratio of the polystyrene graft-polymerized to the propylene copolymer to the iQ polystyrene, so-called graft efficiency, was determined to be 79.4 fifA%.

Example-2 21 kg of pure water in an autoclave with a capacity of 50 liters
and 420 g of tribasic calcium phosphate and 0.63 g of sodium dodecylbenzenesulfonate as suspending agents. was added to form an aqueous suspension, and to this was added propylene-divinylbenzene copolymer particles (propylene-containing a
299.46 2%, divinylbenzene containing H0,54
iQ%, Ml 6.4) 7 kg was suspended by stirring.

Separately, 70 g of t-butyl peroxybenzoate (decomposition temperature: 104°C) was used as a polymerization initiator, and α was used as a chain transfer agent.
- Methyl styrene dimer (manufactured by NOF Corporation) 35 g
was dissolved in 3.5 kg of styrene, and this was added to the suspension system, and 10.5 kg of styrene-modified propylene copolymer particles were obtained using the same force method as in Example 1. The particles were free of fusion, agglomeration, damage, etc., and were ready for use in molding.

Furthermore, the grafting efficiency was determined by the same method as in Example 1 and was found to be 44.0% by weight.

Comparative example-1 20 kg of pure water in an autoclave with an internal volume of 50 liters
400 g of tricalcium phosphate and 0.6 g of sodium dodecylbenzenesulfonate as suspending agents were added to make an aqueous suspension, and to this was added a powdery propylene-divinylbenzene copolymer with a particle size of 0.5 mm or less (propylene content: 99.74% by weight, divinylbenzene content - 0.26% by weight, Ml 4.1)2. 5 kg were suspended by stirring. Separately, as a polymerization initiator, t-butyl peroxybenzoate (decomposition temperature = 104°C) 25fr
was dissolved in 2.5 kg of styrene, this was added to the suspension system, and polymerization was carried out in the same manner as in Example 1. The obtained particles were agglomerated due to fusion, making it difficult to extract them from the reactor.

Example-3 1.2k pure water in an autoclave with an internal volume of 3 liters
g and 24 g of tricalcium phosphate and 0.04 g of sodium dodecylbenzenesulfonate as suspending agents to form an aqueous suspension, and to this was added propylene-divinylbenzene copolymer particles with a particle size of 4 to 5 mm (propylene content: 99 g). .77% by weight, containing divinylbenzene ff10.2
3 weight 96, Ml 20.3) 400K was suspended by stirring. Separately, 0.6 g of t-butyl peroxide (decomposition temperature = 104°C) as a polymerization initiator was dissolved in 200 g of methyl methacrylate, and this was added to the suspension system, and methyl methacrylate was modified in the same manner as in Example 1. 600 g of propylene copolymer particles were obtained. This particle is
There was no fusion, clumping, damage, etc., and the product was ready to be used for molding. In addition, when the grafting efficiency was determined using the same method as in Example 1, it was found to be 54.0ffim%.

Example-4 Instead of the propylene-divinylbenzene copolymer of Example-3, ethylene-propylene-divinylbenzene copolymer (ethylene content 58.9% by weight, propylene content 40.93% by weight, divinylbenzene content) ff10.
17 weight;%) was used in the same manner as in Example-3,
Methyl methacrylate modified propylene copolymer particles 60
Obtained 0g.

The particles were free from melting, agglomeration, damage, etc., and were ready to be used for molding.

Grafting efficiency was determined by the same method as in Example 1 and was found to be 65.3% by weight.

Comparative Example-2 The same procedure as Example-1 was carried out except that propylene polymer particles (Ml6) were used instead of the propylene-divinylbenzene copolymer particles of Example-1, and 10.5 kg of styrene-modified propylene polymer particles were prepared. I got it. This particle is fused,
There was no clumping or damage, and the product was ready for molding.

The grafting efficiency was determined in the same manner as in Example 1 and was 16.0% by weight.

Comparative Example-3 Polypropylene (Mitsubishi Polypro FYb manufactured by Mitsubishi Yuka Co., Ltd.
(Ml2.3)), polystyrene (manufactured by Mitsubishi Monsando Kasei Co., Ltd. [Dialex JHF77, Ml5.5), styrene-modified propylene copolymer particles obtained in Example-1, and styrene obtained in Comparative Example-2. Modified propylene polymer particles were used in the proportions shown in Table 1, and the resin temperature was 225°C using a Mitsubishi Heavy Industries HM extruder (diameter 50).
A sheet with a thickness of 0.3 was formed at a take-up speed of 2.2 m/min.

These sheets were evaluated in various ways. The results are shown in the table.

Claims (1)

[Scope of Claims] A method for producing novel polymer particles, characterized by comprising the following steps (A) and (B). (A) Formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R^1: H or CH_3 R^2: Hydrocarbon group having 1 to 6 carbon atoms n: 0 or 1) Dialkenylbenzene and propylene represented by 100 parts by weight of copolymer particles mainly consisting of 100 parts by weight of copolymer particles, 5 to 200 parts by weight of vinyl or vinylidene monomer, and a radical polymerization initiator whose decomposition temperature is 85 to 130°C to obtain a half-life of 10 hours. An aqueous suspension containing 0.01 to 3 parts by weight per 100 parts by weight of the vinyl or vinylidene monomer is heated under conditions that do not substantially cause decomposition of the initiator to convert the vinyl or vinylidene monomer into an olefin. The polymer particles are impregnated to reach an amount of less than 20% by weight of free vinyl or vinylidene monomer. (B) The temperature of the aqueous suspension is raised to complete the polymerization of the vinyl or vinylidene monomer.